Dental floss is usually supplied in spools, and for use a short length is cut from the spool, wrapped around fingers of opposite hands, and inserted into the mouth and between the teeth. The manipulation of floss between the teeth with the fingers is difficult, and the need for a sufficient length of floss to wrap around the fingers results in the waste of a substantial amount of floss. Devices for holding floss for use in the mouth have been proposed; however, the prior art devices have not been entirely satisfactory, and a floss holder which is convenient and easy to use, which provides proper tension on the floss, and which includes a mechanism for the positive advance of floss to replace used portions of floss with fresh portions would be an improvement over the prior art devices.